Visible-light-assisted degradation of organic pollutants using CuO micro-flowers/PPy nanowires/reduced graphene oxide ternary heterostructure

Organic micropollutants such as antibiotics and dyes persist in water and are often poorly removed by conventional treatment. Semiconductor-based photocatalysis provides an efficient visible-light-driven route to degrade these contaminants. Herein, a novel copper oxide (CuO)/polypyrrole (PPy)/reduced graphene oxide (rGO) composite was synthesized via a simple hydrothermal method. The physicochemical properties of the as-prepared photocatalysts were characterized using XRD, XPS, Raman, FESEM-EDX, UV–vis, BET, PL analyses. Moreover, the photocatalytic activity was evaluated by the degradation of tetracycline (TC) and methyl orange (MO) under visible light for 240 min. The CuO/PPy/rGO ternary composite exhibited markedly higher photocatalytic performance than bare CuO and CuO/PPy, achieving 99% degradation of TC and 60% degradation of MO. Notably, the improved performance is attributed to rGO incorporation, which likely forms a conductive, high-surface-area structure that promotes charge separation and interfacial electron transport. Kinetic analysis showed a higher pseudo-first-order rate constant for TC degradation over the ternary composite (kapp = 0.010 min −1 ) than bare CuO (0.003 min −1 ), confirming the superior activity of the ternary catalyst. Additionally, HPLC analysis was employed to further confirm the degradation efficiency of TC and MO. The catalyst also retained high activity over five cycles, and radical-trapping experiments identified •O 2 − as the dominant reactive species. Overall, the CuO/PPy/rGO composite offers a durable and efficient visible-light photocatalyst for sustainable wastewater treatment.